Compressor

ABSTRACT

Compressor including a chamber having a muffler room therein for introducing refrigerant compressed at a compression part, a cover on top of the chamber for closing an upper part of the muffler room, and a discharge muffler including a first coating gasket having a base part with coated layers on upper and lower surfaces for sealing between the chamber and the cover, thereby reducing noise and simplifying assembly.

This application claims the benefit of the Korean Application Nos. P2003-080520 and P2003-08051 both filed on Nov. 14, 2003, and is a Divisional of U.S. patent application Ser. No. 10/852,459 filed May 25, 2004, which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to compressors, and more particularly, to a compressor which has reduced noise, and a structure easy to assemble.

2. Background of the Related Art

In general, the compressor is provided with a compression part for compressing refrigerant by means of reciprocating movement, a motor part for driving the compression part, and an enclosed container for holding the compression part and the motor part therein. The compressor compresses refrigerant, a working fluid of a refrigerator or the like, from a low temperature, and low pressure state to a high temperature, and high pressure state. The compression of the refrigerant is made by a compression force applied with a piston reciprocating along a cylinder in the compression part. FIG. 1 illustrates a section of a related art compressor.

Referring to FIG. 1, the compressor is provided with a container 1 having a lower container 1 a and an upper container 1 b on an outside of the compressor. The container 1 forms an enclosed space inside thereof, containing a motor part 4 having a stator 2 and a rotor 3. The container also has a suction pipe for drawing the refrigerant into an inside of the compressor, and a discharge pipe for discharging the refrigerant to an outside of the compressor.

The stator 2 has slots each with a coil wound therearound a number of times, and the rotor 3 is rotatably provided to an inside of the stator 2. The rotor 3 has a vertical pass through hole 3 a in a center part, in which a rotation shaft 5 is mounted. The rotation shaft 5 rotates together with the rotor 3 once a power is provided to the coil.

For absorbing vibration taken place in driving the motor part, there are a plurality of springs ‘S’ under the stator 2. Accordingly, since the vibration is absorbed by the springs ‘S’, vibration transmitted to an outside of the compressor is reduced.

There is a balance weight 5 b in an upper part of the rotation shaft projected in a radial direction for stabilizing the rotation speed of the rotation shaft 5. There is an eccentric part 5 a on the balance weight 5 b eccentric from an axis of the rotation shaft 5. The eccentric part 5 a is connected to the piston with a connecting rod 9.

In the meantime, the rotation shaft 5 has an oil feed for pumping up oil held on a bottom of the lower container 1 a. If the rotation shaft 5 rotates, the oil is pumped up along the oil feed, and sprayed from the eccentric part 5 a to a cylinder 7, the piston 8, and the connecting rod 9.

There is a cylinder block 6 over the motor part. The cylinder block 6 has a boss 6 a in a central part projected downward. The rotation shaft 5 is passed through, and inserted in the boss 6 a. The cylinder 7 is on the cylinder block 6 fabricated as one unit. The cylinder 7 has a space therein for compressing the refrigerant, along which space the piston 8 reciprocates.

There is the connecting rod 9 between the piston 8 and the eccentric part 5 a. The connecting rod 9 converts rotation of the eccentric part 5 a into a horizontal reciprocating movement. For this, the connecting rod 9 has one end connected to the piston 8, and the other end connected to the eccentric part 5 a.

The connecting rod 9 has a hole in the other end having the eccentric part 5 a rotatably inserted therein. There is a sleeve 10 between the eccentric part 5 a and the hole. The sleeve 10 makes the hole and the eccentric part 5 a to come into close contact. As the piston 8 reciprocates, processes of suction, compression and discharge are made, repeatedly.

In the meantime, there is a valve assembly 11 at one side of the cylinder 7 for controlling refrigerant suction into, discharge from the cylinder 7. There is a head cover 12 at an outer side of the valve assembly 11 for isolating the refrigerant being drawn, from the refrigerant being discharged.

There is a suction muffler 13 at a suction side of the head cover 12 for reducing noise from the refrigerant being drawn into the cylinder 7, and preventing the refrigerant from being heated.

There is a discharge muffler (not shown) adjacent to the cylinder 7. The discharge muffler has one end connected to a discharge side of the head cover 12, and the other side connected to a loop pipe 14. The loop pipe 14 is connected to a discharge pipe 16 for discharging the high temperature, and high pressure refrigerant from the cylinder 7 to an outside of the compressor.

The loop pipe 14 is bent for a number of times for absorbing vibration caused by the refrigerant flowing through an inside of the loop pipe 14, and there is a coil weight 14 a on an outside of the loop pipe 14. The coil weight 14 a, having a form of a spring, absorbs vibration taken place at the loop pipe 14. FIG. 2 illustrates a perspective view of a related art discharge muffler.

Referring to FIG. 2, the discharge muffler 30 is on the cylinder block 6. The discharge muffler 30 attenuates noise taken place when the refrigerant is compressed by a piston in a compression chamber 7 a of the cylinder 7.

The discharge muffler 30 is provided with a chamber 31, a cover 33, and a bolt 35. The chamber 31 is on the cylinder block 6, and has a space form therein. The cover 33 is convex upwardly for covering a top of the chamber 31.

The chamber 31 has a loading surface 31 a in an upper part for loading a rim of the cover 33 thereon, and a hole 31 b projected upward from a bottom surface. The bolt 35 passes through a central part of the cover 33, and fastened to the hole 31 b.

In the meantime, for preventing the refrigerant discharged into an inside of the discharge muffler 30 from leaking, a sealing member 37 is provided between the loading surface 31 a and the cover 33. FIG. 3 illustrates a disassembled perspective view of a valve assembly employed in a related art compressor.

Referring to FIG. 3, the valve assembly 11 is provided with a valve plate 21, a valve spring 25, and a retainer 27. The valve plate 21 has a recess 21 a in a front surface having a discharge valve 23, the valve spring 25, and the retainer 27 received therein. The discharge valve 23 has an upper surface with the valve spring 25 in close contact therewith, and the retainer 27 is fitted on an upper surface of the valve spring 25 for preventing the discharge valve 23 and the valve spring 25 from playing. There is a gasket 29 between the valve plate 21 and the head cover 12, and there is a suction valve ‘V’ on a rear surface of the valve plate 21.

The recess 21 a has a discharge hole 21 b projected upward, with a seat surface 21 c around the discharge hole 21 b in contact with the discharge valve 23. There is a suction hole under the recess 21 a.

The discharge valve 23 has a cover 23 a to be brought into contact with the seat surface 21 c to open/close the discharge hole 21 b, and a first fixing part 23 b. The valve spring 25 has a bending part 25 b bent upward, and a second fixing part 25 a to be brought into contact with the first fixing part 23 b. The retainer 27 is fitted on the valve spring 25, and the first, and second fixing parts 23 b, and 25 a are clamped between the recess 21 a and the retainer 27.

The related art compressor has the following problems.

First, there have been frequent cases when the fixing bolt is fastened under a state accurate loading of the sealing member on the loading surface failed, to cause one side of the sealing member broken, resulting in leakage of the refrigerant and noise, and a portion of the broken sealing member to block the pipe.

Second, the repeated hitting of the discharge valve onto the valve spring of the valve assembly increases noise when the refrigerant is discharged from the compressor.

Third, the many number of components of the valve assembly leads a structure of the valve assembly complicate. Accordingly, the valve assembly costs high, and assembly of the valve assembly is difficult.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a compressor that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a compressor which can be assembled with easy and prevent noise.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, the compressor includes a chamber having a muffler room therein for introducing refrigerant compressed at a compression part, a cover on top of the chamber for closing an upper part of the muffler room, and a discharge muffler including a first coating gasket having a base part with coated layers on upper and lower surfaces for sealing between the chamber and the cover.

The base part is a disk of metal having a hole at a central part, and the metal is steel. In more detail, the first coating gasket has a form of a disk having a hole in a central part and a predetermined width in a radial direction for choking a communication part between the muffler room and a lower space of the cover.

The cover and the first coating gasket have central holes respectively, the chamber has a fastening hole in a bottom, and the compressor further includes a bolt passed through the holes and fastened to the fastening hole. The central hole in the first coating gasket has a diameter greater than the bolt, and the fastening hole is projected upward from the bottom of the chamber.

The bolt includes a head part held at an upper surface of the cover, and a screw part under the head part for fastening to the fastening hole. The cover and the first coating gasket are clamped between the head part and the chamber as the bolt is fastened.

The cover has an extension from a rim in a lower part thereof, and the chamber has a loading part on an inside wall for loading the extension. The coating layer is formed of elastic rubber.

The compressor further includes a loop pipe at one side of the cover as a refrigerant flow passage from the discharge muffler.

The compression part includes a cylinder for reciprocating of a piston along an inside circumferential surface to compress the refrigerant, a cylinder block having the cylinder and the discharge muffler fixed to an upper part thereof, and a valve assembly in front of the cylinder for regulating suction and discharge of the refrigerant with reference to the cylinder.

The chamber is formed as one unit with the cylinder block, and the chamber has a lower part connected to a refrigerant discharge hole of the valve assembly.

In other aspect of the present invention, there is provided a compressor including a valve assembly including a suction plate in front of a cylinder for compressing refrigerant therein, having a suction valve and a discharge passage a valve plate in front of the suction plate, having a suction hole and a discharge hole, a discharge plate in front of the valve plate, having a discharge valve for selective opening of the discharge hole, and a suction passage, a head cover in front of the discharge plate, for isolating the refrigerant being drawn, from the refrigerant being discharged, and a second coating gasket between the discharge plate and the head cover, having a retainer for regulating opening of the discharge plate and a suction passage in one side part thereof.

The second coating gasket includes a base part of metal, and coated layers on outside surfaces of the base part, and the metal is steel.

The coated layer is formed of elastic rubber. The second coating gasket has an opening in an inside part, and the retainer is formed across the opening, and the retainer is bent at opposite side parts to project toward the head cover.

The retainer is formed at a position in contact with a front surface of the discharge valve, and the retainer deforms elastically in a forward direction of the second coating gasket when the discharge valve is opened. The retainer restores from the elastic deformation after discharge of refrigerant is finished, to push close the discharge valve.

The suction valve is formed as one unit with the suction plate, and the discharge valve is formed as one unit with the discharge plate.

The suction valve is opened as the suction valve is pushed backward of the suction plate by a pressure of the refrigerant while movement of the suction valve in a forward direction of the suction plate is held. Opposite to this, the discharge valve is opened as the discharge valve is pushed forward of the discharge plate by a pressure of the refrigerant while movement of the discharge valve in a backward direction of the discharge plate is held.

Respective plates and the head cover have holes at four corners thereof, and bolts are inserted in the holes, respectively. The bolts have one ends fastened to a front surface of the cylinder respectively, and the plates, and the head cover are clamped between the head parts of the bolts, and the front surface of the cylinder.

It is to be understood that both the foregoing description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention.

In the drawings;

FIG. 1 illustrates a section of a related art compressor;

FIG. 2 illustrates a perspective disassembled view of a related art discharge muffler;

FIG. 3 illustrates a perspective disassembled view of a related art valve assembly;

FIG. 4 illustrates a perspective disassembled view of a discharge muffler in accordance with a preferred embodiment of the present invention;

FIG. 5 illustrates a perspective view of a first coating gasket in accordance with a preferred embodiment of the present invention;

FIG. 6 illustrates a section of a discharge muffler in accordance with a preferred embodiment of the present invention;

FIG. 7 illustrates a perspective disassembled view of a valve assembly in accordance with a preferred embodiment of the present invention; and

FIG. 8 illustrates a perspective view of a second coating gasket in accordance with a preferred embodiment of the present invention, with a partial section.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. In describing embodiments of the present invention, same parts will be given the same names and reference symbols, and repetitive description of which will be omitted.

Embodiments of the compressor of the present invention will be described with reference to FIGS. 4 to 8. FIG. 4 illustrates a perspective disassembled view of a discharge muffler in accordance with a preferred embodiment of the present invention, and FIG. 5 illustrates a perspective view of a first coating gasket in accordance with a preferred embodiment of the present invention.

The compressor of the present invention includes a hermetic container, a motor part, and a compression part. The motor part is in the hermetic container, for converting an electric energy into a kinetic energy. The compression part compresses the refrigerant by using the kinetic energy converted by the motor part.

There is a cylinder block 101 over the motor part, and the cylinder block 101 has a boss 106 projected downward from a central part. There is a rotation shaft (not shown) passed through a hole 106 a in the boss 106 for transmitting a rotation force from the motor part to the compression part.

The cylinder block 101 has fastening parts 103 projected downward from four corners, to which the stator of the motor part is fastened with bolts.

There is a cylinder 150 in an upper part of the cylinder block 101 having a compression chamber 150 a therein for compressing the refrigerant. When a piston reciprocates along the compression chamber 150 a horizontally, suction, compression, and discharge processes of the refrigerant are repeated. The cylinder 150 is fabricated with the cylinder block as one unit, or a separate cylinder 150 is fastened to an upper surface of the cylinder block 101 with bolts.

In the meantime, a discharge muffler 300 is provided on one side of the cylinder 150. The discharge muffler 300 attenuates noise emitted when the refrigerant compressed at the compression chamber 150 a is discharged. The discharge muffler 300 includes a chamber 301, a cover 400, and a first coating gasket 500.

The chamber 301 is one unit with the cylinder block 101, and has a muffler room 310 therein. There is a semispherical cover 400 convex upward on the chamber 301. A loop pipe ‘P’ is passed through one side of the cover 400. The first coating gasket 500 is between the chamber 301 and the cover 400.

The muffler room 310 in the chamber 301 is a space for absorbing noise of the refrigerant compressed at the compression chamber 150 a. The muffler chamber 310 has a fastening hole 310 a projected upward from a bottom for fastening a bolt 450 thereto.

There is a loading part 330 on an inside wall of an upper part of the chamber 301 for loading a rim of the cover. The cover 400 has an extension 410 from the rim. Accordingly, the extension 410 is loaded on the upper surface of the loading part 330. The bolt 450 is inserted through a hole 400 a in an upper part of the cover 400.

FIG. 6 illustrates a section of a discharge muffler in accordance with a preferred embodiment of the present invention.

Referring to FIG. 6, the bolt 450 has a head part 450 a and a screw part 450 b. An upper surface of the cover 400 is clamped with the head part 450 a. The screw part 450 b is fastened to a fastening hole 310 a in an inside of the chamber 301. The deeper the screw part 450 b is fastened to the fastening hole 310 a, the stronger the head part 450 a clamps the cover 400.

The first coating gasket 500 is between the extension 410 of the cover 400 and the loading part 330 of the chamber 301. The first coating gasket 500 of a ring form prevents the refrigerant from leaking to an outside of the discharge muffler 300.

Referring to FIG. 5, the first coating gasket 500 includes a base part 510 having coated layers 530, and 550 on upper, and lower surfaces, respectively.

The base part 510 is formed of metal, such as steel. The coated layers 530, and 550 are formed of an elastic material, coated on the upper and lower surfaces of the base part 510.

Accordingly, as the bolt 450 is fastened to the fastening hole 310 a, the coated layers 530, and 550 are compressed, to seal between the loading part 330 and the extension 410. It is preferable that the coated layer is formed of rubber.

The first coating gasket 500 has a form of a disk having a hole at a center, and a width in a radial direction. The first coating gasket 500 is between the muffler room 310 and the cover 400, and chokes a part making an inside space (muffler room) of the chamber 301 and an inside space of the cover 400 in communication. Thus, the spaces are formed, and transmission of the noise of the refrigerant from the muffler room 310 to an upper part of the discharge muffler 300 is suppressed.

In the meantime, the loop pipe P is at one side of the cover 400, for discharging the refrigerant, compressed at the cylinder 150 and introduced into the muffler room 310, to an outside of the discharge muffler through the loop pipe P.

The first coating gasket 500 has a hole 500 a for leading the refrigerant from the muffler room 310 to the cover 400. The hole 500 a has a diameter greater than the bolt 450. Therefore, the refrigerant flow upward through a gap between an outside circumferential surface of the bolt 450 and the hole 500 a. Thereafter, the refrigerant is lead to the loop pipe ‘P’.

A refrigerant flow in the discharge muffler 200 is as follows.

The refrigerant compressed at the compression chamber 150 a of the cylinder 150 is introduced into the muffler room 310. The noise from the refrigerant is blocked at the first coating gasket 500 on an upper surface of the muffler room 310. Therefore, noise transmitted to an outside of the discharge muffler 200 is reduced.

The refrigerant is introduced into the cover 400 between the outside circumferential surface of the bolt 450 and the hole 500 a of the first coating gasket 500. The refrigerant is discharged to an outside of the discharge muffler 300 through the loop pipe ‘P’.

In the meantime, a valve assembly 100 is provided in front of the cylinder 150.

FIG. 7 illustrates a perspective disassembled view of a valve assembly in accordance with a preferred embodiment of the present invention, and FIG. 8 illustrates a perspective view of a second coating gasket in FIG. 7, with a partial section.

The valve assembly regulates suction of the refrigerant into the cylinder, as well as discharge of refrigerant compressed at the cylinder by the piston. The valve assembly 100 includes a valve plate 110, a suction plate 130, a discharge plate 140, a second coating gasket 200, and a head cover 170.

The suction plate 130 is in rear of the valve plate 110, and the discharge plate 140 is in front of the valve plate 110. The head cover 170 is on a front surface of the discharge plate 140 for isolating the refrigerant being drawn, from the refrigerant being discharged, and the second coating gasket 200 is between the discharge plate 140 and the head cover 170 for preventing leakage of the refrigerant.

The valve plate 110 is a square plate having a suction hole 110 a for passing the refrigerant being drawn, and a discharge hole 110 b for discharging the refrigerant.

The suction plate 130 has a suction valve 130 a formed as one unit. The suction valve 130 a having one end connected to the suction plate 130 selectively opens/closes the suction hole 110 a. For an example, when the suction valve 130 a is pushed backward by a pressure of the refrigerant, the suction valve 130 a is opened.

Also, the suction plate 130 has a discharge passage 130 b above the suction valve 130 a in communication with the discharge hole 110 b. Therefore, the refrigerant from the cylinder is lead to the discharge hole 110 b through the discharge passage 130 b.

In the meantime, the discharge plate 140 is a square plate having a discharge valve 140 a and a suction passage 140 b. The discharge valve 140 a opening/closing the discharge hole 110 b is formed as one unit with the discharge plate 140. The discharge valve 140 a connected to the discharge plate 140 opens/closes the discharge hole 110 b, selectively. For an example, when the discharge valve 140 a is pushed forward by a pressure of the refrigerant, the discharge valve 140 a is opened.

The discharge plate 140 has a suction passage 140 b at a position facing the suction hole 110 a below the discharge valve 140 a. Accordingly, the refrigerant opens the suction valve 130 a after passing through the suction passage 140 b and the suction hole 110 a, and is drawn into the cylinder.

The head cover 170 covers a front surface of the discharge plate 140. The head cover 170 has a dividing wall for isolating the refrigerant being drawn, and the refrigerant being discharged.

The second coating gasket 200 is between the discharge plate 140 and the head cover 170 for preventing the refrigerant from leaking. It is preferable that the second coating gasket 200 is provided in front of the discharge plate 140, because the refrigerant discharged through the discharge valve 140 a of the discharge plate 140 is in a state compressed to a high pressure.

Referring to FIG. 8, the second coating gasket 200 is a square plate having a base part 210 and coated layers 230, and 230′. The base part 210 is formed of metal like steel, and the coated layers 230, and 230′ are formed on both surfaces of the base part 210, respectively.

The coated layer 230, or 230′ is formed of elastic natural rubber or a synthetic rubber. Moreover, for preventing corrosion from the refrigerant or oil, it is preferable that the coated layers 230 and 230′ are formed of a chemical resistance material.

In the meantime, the second coating gasket 200 has a retainer 250 in an inside formed as one unit. The second coating gasket 200 has an opening in an inside part, and the retainer crosses the opening. Opposite sides of the retainer 250 are bent toward a forward direction of the second coating gasket 200.

The retainer 250 is formed at a position opposite to the discharge valve 140 a. Therefore, if the discharge valve 140 a is opened, an end of the discharge valve 140 a is brought into contact with a rear surface of the retainer 250, when the retainer 250 is elastically deformed forwardly. That is, an extent of opening of the discharge valve 140 a is restricted by the retainer 250. The coating gasket 200 has a suction passage 200 b in a lower part in communication with the suction hole 110 a and the suction passage 200 b.

Referring to FIG. 7, the suction plate 130, the valve plate 110, the discharge plate 140, the coating gasket 200, and the head cover 170 have holes 130 c, 110 c, 140 c, and 170 c at four corners thereof. By fastening bolts through the holes, the valve assembly 100 is fixed to a front surface of the cylinder.

Referring to FIGS. 4 and 7, the head part of the bolt ‘B’ clamps the head cover 170, the screw part of the bolt ‘B’ passes through above holes, and the holes (150 b in FIG. 4) in the front part of the cylinder (150 in FIG. 4), and fastened to nuts. According to this, the second coating gasket 200, the discharge plate 140, the valve plate 110, and the suction plate 130 are clamped between the head cover 170 and the front surface of the cylinder rigidly in an above order. The discharge valve 140 a on the discharge plate 140 is fixed at a position opposite to the retainer 250 on the coating gasket 200.

The operation of the valve assembly 100 will be described in detail.

The refrigerant drawn through a suction side of the head cover 170 passes the suction passages 200 b, and 150 b in succession, and passes the suction hole 110 a in the valve plate 110. Then, the refrigerant pushes open the suction valve 130 a on the suction plate 130, is introduced into an inside of the cylinder, and compressed by the piston.

In this instance, when the piston moves forward along the inside circumferential surface of the cylinder, the suction valve 130 a is closed by a pressure of the refrigerant being compressed. Then, the refrigerant compressed by the piston passes the discharge passage 130 b and the discharge hole 110 b, pushes open the discharge valve 140 a on the discharge plate 140, and is discharged through a discharge side of the head cover 170. In this instance, the discharge valve 140 a pushes the retainer 250 to deform the retainer 250 in a forward direction.

In this instance, movement of the suction valve 130 a in a forward direction of the suction plate 130 is held, and the suction valve 130 a is pushed open in backward of the suction plate 130 by a pressure of the refrigerant.

In the meantime, after discharge of the refrigerant is finished, the retainer 250 restores from the elastic deformation, when the discharge valve 140 a pushed by the retainer 250 closes the discharge hole 110 b.

As has been described, the compressor of the present invention has the following advantages.

First, the first coating gasket prevents noise of the refrigerant from transmitting to an upper part. According to this, since no partition plate is required under the cover for dividing the space, the discharge muffler of the present invention has a simple assembly structure, and high productivity.

Second, the steel inside of first coating gasket prevents the first coating gasket from breaking even if the first coating gasket is pressed.

Third, since the retainer is formed as one unit with the second coating gasket, and also serves as a valve spring, a structure of the valve assembly is simple, thereby improving a productivity of the hermetic compressor of the present invention.

Fourth, the second coating gasket is fabricated in a form the steel is coated with a coating layer. Therefore, the second coating gasket is not damaged even if the second coating gasket is pressed down in a fastening process.

Fifth, the coating layer on an underside surface of the retainer the discharge valve is to be brought into contact thereto prevents noise caused by repetitive contact between the discharge valve and the retainer.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. 

1. A compressor comprising a valve assembly, comprising: a suction plate in front of a cylinder for compressing refrigerant therein, having a suction valve and a discharge passage; a valve plate in front of the suction plate, having a suction hole and a discharge hole; a discharge plate in front of the valve plate, having a discharge valve for selective opening of the discharge hole, and a suction passage; a head cover in front of the discharge plate, for isolating the refrigerant being drawn, from the refrigerant being discharged; and a second coating gasket between the discharge plate and the head cover, having a retainer for regulating opening of the discharge plate and a suction passage in one side part thereof.
 2. The compressor as claimed in claim 1, wherein the second coating gasket comprises: a base part of metal; and coated layers on outside surfaces of the base part.
 3. The compressor as claimed in claim 2, wherein the metal is steel.
 4. The compressor as claimed in claim 2, wherein the coated layers are formed of elastic rubber.
 5. The compressor as claimed in claim 1, wherein the second coating gasket has an opening in an inside part, and wherein the retainer is formed across the opening.
 6. The compressor as claimed in claim 5, wherein the retainer is bent at opposite side parts to project toward the head cover.
 7. The compressor as claimed in claim 5, wherein the retainer is formed at a position in contact with a front surface of the discharge valve.
 8. The compressor as claimed in claim 7, wherein the retainer deforms elastically in a forward direction of the second coating gasket when the discharge valve is opened.
 9. The compressor as claimed in claim 7, wherein the retainer restores from the elastic deformation after discharge of refrigerant is finished, to push the discharge valve closed.
 10. The compressor as claimed in claim 1, wherein the suction valve is formed as one unit with the suction plate.
 11. The compressor as claimed in claim 1, wherein the discharge valve is formed as one unit with the discharge plate.
 12. The compressor as claimed in claim 1, wherein the suction valve is opened as the suction valve is pushed backward of the suction plate by a pressure of the refrigerant while movement of the suction valve in a forward direction of the suction plate is held.
 13. The compressor as claimed in claim 1, wherein the discharge valve is opened as the discharge valve is pushed forward of the discharge plate by a pressure of the refrigerant while movement of the discharge valve in a backward direction of the discharge plate is held.
 14. The compressor as claimed in claim 1, wherein respective plates and the head cover have holes at four corners thereof, and bolts are inserted in the holes, respectively.
 15. The compressor as claimed in claim 14, wherein the bolts have ends fastened to a front surface of the cylinder, and wherein the plates and the head cover are clamped between the heads of the bolts, and the front surface of the cylinder. 